This invention relates to buoyant illuminating devices, and more particularly concerns devices which float on the surface of a body of combustible oil and include an upstanding wick member.
Many devices are known which comprise buoyant wick-holders which may be floated on the surface of a body of combustible oil so that a wick supported on the holder draws oil by capillary action and may be ignited. Some of these devices are disclosed in the prior art, for example U.S. Pat. Nos. 405,736 and 2,246,346 use cork, paste board or the like as buoyant members, which are not only porous, but also are highly absorbant with respect to the oil in which they float. Inevitably, such wick-holders become saturated with oil and since their absorption is not uniform, they tend to tilt while floating, thereby tilting their wicks and resulting in an undesirable appearance. Ultimately such wick-holders may turn over and sink, or may even ignite the oil on which they float.
U.S. Pat. No. 397,011 discloses a wickless float or cup having a central upright tube integral therewith. The cup has appropriate shape and weight so that when the cup is floated on the surface of a body of oil, there is oil in the tube substantially flush with the upper edge of the tube. The upper part of the tube is heated until the oil commences to boil and catch fire, after which the apparatus itself maintains the heat and the oil continues to burn. This device is inherently more expensive because it must be made of metal.
Another buoyant illuminating device is disclosed in U.S. Pat. No. 3,183,688. This device comprises a thin walled body having a central well portion, a walled buoyancy imparting portion surrounding the well portion, and an annular hollow rib portion separating the buoyancy imparting portion from the well portion. An annular ring of oil within the hollow rib portion serves to insulate the well portion from the buoyancy imparting portion and to dissipate heat and thereby eliminate the possibility of heat distortion. The bottom wall of the well portion has openings for admitting oil into the well portion for impregnating a mounted wick.
British specification No. 1,380,358 discloses another floating wick-holder. A semi-cylindrical member which is molded or vacuum-formed has diametral crisscross channels. Oil flows over the channels to feed a wick supported in the area traversed by the channels. Airtight cavities provide buoyancy. Because the channels are relatively deep and crisscross the entire member this configuration has proven to be unstable. Further the cavities, particularly in the embodiment disclosing pie-shaped cavities, are not spaced sufficiently from the wick. When the wick is ignited the portions of the member which form the cavities tend to melt in areas near the wick. This usually causes at least one cavity to collapse and the wick-holder overturns. The area traversed by the channels where the wick is located is substantially flat and air bubbles may become trapped beneath this region prohibiting the wick-holder from floating levelly.